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INDEPTH: HEALTH
Vaccination: A Grant of Immunity
CBC News Online | April 27, 2004

Throughout the early history of humanity great plagues killed millions of people. Often, healers noticed that, with some diseases, once a person had become ill they didn't become reinfected. One of the first written records of acquired immunity came from the Greek author Thucydides who noted during the great plague of Athens, in the fifth century BC, that the people who survived did not get the disease again.

It was in China in the 10th century that an early form of vaccination called variolation was first used to combat smallpox. Healers would take samples of the lesions caused by smallpox, grind them into powder, and put some under the skin or inhale them through the nose.

Variolation reached Europe in the 18th century. In 1721, a royal physician in London experimented on prisoners and found it was a somewhat successful way of preventing smallpox. Those who were inoculated usually had a mild form of the illness, though there were deaths.

The idea of vaccination began with an English doctor named Edward Jenner, who began practising in Berkeley, Gloucestershire, in 1773. Jenner noted that local farmers believed anyone who had become infected with cowpox wouldn't get the more deadly smallpox. In 1796, Jenner began an experiment that today would be considered unethical. He inoculated an eight-year-old boy with cowpox and later exposed him to smallpox. The boy did not get the disease.

Jenner published his first treatise in 1798 and hospitals in London began vaccination soon after. In 1802, the British Parliament awarded Jenner 10,000 to continue his research. Around the world, individuals and countries began to adopt vaccination by inoculation. In 1805, both Mexico and Guatemala were vaccinating their population. In 1807, Bavaria made vaccination compulsory.

From the beginning, some people refused to believe vaccination worked, and refused to be vaccinated. When the British House of Commons passed an act in 1853 to make it compulsory, an anti-vaccination movement grew up. In 1870, a man named George Gibbs complained of "medical spies" forcing themselves into people's homes. In 1898, Britain changed the act to allow people to opt out of vaccination programs.

In France, Louis Pasteur was researching infectious diseases by growing bacterial cultures and found that old, weakened bacteria didn't cause diseases in animals. In 1885, he first used weakened rabies bacteria to stave off an infection. Five years later, two researchers found that animals inoculated with small amounts of toxin could become immune and this led to vaccinations for diphtheria and tetanus.

Advances since World War II

It was only after the Second World War, with the new technology and communications and the establishment of the World Health Organization, that there were widespread efforts to promote vaccination.

There were also new advances, such as the discovery of the polio vaccine in 1954, which used a killed version of the virus. The injectable vaccine was replaced with an oral version in 1962, and according to the WHO, the vaccine "dramatically" reduced the number of polio cases.

IN 1980, the WHO's campaign to eradicate smallpox was considered successful.

The World Health Organization estimates that vaccination saves millions of lives each year-and it says that the lack of vaccination kills two million children a year, most of them in the developing world. The WHO also estimates that 90,000 children fall victim to polio each year, a disease that has been prevented by immunization in the west since the 1950s.

The WHO had announced the aim of eliminating polio by the year 2000. By 1995, the WHO estimated that 78 per cent of the world's children had received three doses of polio vaccine. The same year, 146 countries reported no cases of polio. Although the WHO did not make its goal, it says in most of the remaining areas, polio can be described as "low-incidence."

Although the WHO set a target of immunizing 90 per cent of the world's children against measles, the campaign has been less successful than the one against polio. The organization is now trying for a new target, cutting measles deaths by 50 per cent by 2005.

The problem, the WHO says, is that thousands of measles cases continue to occur in the developing world, especially in Africa. The highest transmission rates occur in areas of dense population, where people live in crowded cities.

Anti-vaccination fears

The British Medical Journal says, "immunization against infectious disease has probably saved more lives than any other public health intervention apart form the provision of clean water." It notes that improved living conditions are also contributing to better lives.

The BMJ notes that without vaccination, smallpox would not have been eliminated from the world-or at least smallpox is its wild state.

At the same time, there is a small but growing anti-vaccination movement.

What the BMJ calls "a vocal minority of parents" in Britain are opposing vaccination, believing that the vaccination itself could be more dangerous than the disease. But, as the journal points out, diseases such as measles, diphtheria and polio are still common among unimmunized populations and could spread easily among a family or community that forgoes immunization.

Dr. Ron Gold, a former head of infectious diseases at the Hospital for Sick Children in Toronto, told The Current that a lot of parents fear the things that could happen with vaccinations, and that fear makes them lose sight of the problems vaccinations prevent. He adds that vaccinations can get the blame for childhood diseases that parents can't otherwise explain.

Health Canada has noted on its Web site that the anti-vaccination movement causes more problems than it solves.

In Ireland in 2000, measles cases rose to 1,200 from 148, after immunization rates fell to 76 per cent. A number of children died.
In 1994, there were 5,000 cases of rubella in Russia after organized immunization was suspended.
In the United Kingdom, after a major drop in pertussis (whooping cough) immunization in 1974, there was an epidemic of whooping cough in 1978, with more than 100,000 cases and 38 deaths.

Gold says in the U.K., publicity over unproven dangers from the measles-mumps-rubella (MMR) vaccine led to a drop in immunization rates; in Russia the problem was fear of HIV from shared needles.

One of the biggest controversies is over thimerosal, an organic mercury compound preservative added to some vaccines. Parents have claimed that thimerosal is linked to autism in their children. In the United States, the Food and Drug Administration investigated thimerosal and concluded that the risk to a baby receiving vaccines was low and theoretical, that thimerosal was dangerous only in high doses. However, the agency recommended that thimerosal be taken out of childhood vaccines.

Gold says, thimerosal was removed from most vaccines because it was no longer needed, and there was a demand for a purer vaccine.

In Canada, there are small amounts of thimerosal in both the diphtheria -polio-tetanus (DPT) and the hepatitis B shot. Gold says the preservative is metabolized as ethyl mercury, which is less dangerous than methyl mercury, and is expelled from the body.

Gold says the thimerosal controversy is not the first. He notes that parents once claimed that the MMR shot was causing autism, until a number of studies showed no connection,

He notes that there has been an increase in the rates of autism but that may be because of an increased awareness of the disease.

Gold also says the increases in autism came long after thimerosal was introduced in the 1930s, so it is hard to see what the link may be. Children usually receive their first vaccinations around their first birthday and autism usually surfaces around 18 months.

Health Canada's Dr. Paul Varughese says the department has created a database to track the side effects of vaccination, a database that is updated regularly from doctors' reports.

Mary James, of Manitoba's Association for Vaccine Damaged Children says Canadians should be concerned about the so-called "five-in-one shot"-the practice of putting five vaccines in one shot. James she says that could overwhelm the "immature neurological and immunological system."

Gold says there is no evidence that vaccines can over-stimulate an immune system. He points out the natural environment challenges a child's immune system every day. Challenges come from protein in food, bacteria on the skin and in the intestinal tract and from viruses.

Bioterrorism

The spectre of terrorism is adding urgency to the debate over vaccination. Countries around the world are stockpiling smallpox vaccine in case of a terror attack.

In the United States, President George W. Bush and the Department of Health and Human Services ordered a mass vaccination program for front-line health care workers.

Many, however, refused to take part because of fear of side effects. By the end of February, the first month of the program 7,354 civilian health care and public health care workers had been vaccinated, out of an estimated 450,000. The plan was that those health workers would then vaccinate up to 10 million people in a threatened area. The Centers for Disease Control reported that only two people had suffered minor side effects. Studies show that for every one million people vaccinated, one or two people could die and 52 become seriously ill.

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DEFINITIONS:

INOCULATE: To impregnate (a person or animal) with the virus or germs of a disease specifically for the purpose of inducing a milder form of the disease and rendering the subject immune from its ordinary attacks. Usually done with a syringe.

VACCINE: A preparation of the causative organism or substance of a disease (or its products) that has been specially treated for use in vaccination.

VACCINATE: To inoculate an individual or group with a vaccine.

Source: Oxford English Dictionary

MEDIA:

On The National Maureen Taylor looks at parental fears over childhood vaccinations ( April 21, 2003 - Runs 16:51)

On As It Happens Mary Lou Finlay talks to Barbara Blakeney of the American Nurses Association who is advising members not to take the smallpox vaccine. ( Jan 24, 2003 - Runs 6:40)

On The Current Anna Maria Tremonti talks to Dr. Ron Gold about the safety of vaccines. (Feb 27, 2003 - Runs 6:39)

On The Current Anna Maria Tremonti talks to David Klein, a lawyer who represent parents in a class-action suit claiming neurological damage from vaccines. (Feb 27, 2003 - Runs 5:24)

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